1. Field of the Invention
This invention relates to metal cellular decking sections useful in the construction of building floors and method of fabricating the same, and more particularly to decking sections having means promoting mechanical bonding of subsequently applied fireproofing material and providing access to the channels for attachment of hanger means.
2. Description of the Prior Art
Metal cellular decking sections are used extensively in the construction of building floors. The decking sections extend between horizontal support beams and support an overlying layer of concrete. The decking sections also provide longitudinal cells serving as raceways for the distribution of various electrical services. To improve the fire-resistant characteristic of the floor structure, fireproofing has been provided on the bottom face of the decking sections. Field spraying of the fireproofing material to the undersurface of the decking sections is a common method of applying such fireproofing. Regardless of the method of application, one difficulty encountered during fire tests of such flooring structures is fireproofing fall-off. One reason proposed for such fireproofing fall-off is the lack of mechanical anchorage for the sprayed material.
Many methods have been proposed to promote mechanical locking between plaster, cementitious fireproofing and other settable material and a substrate. Such use of flat and fluted expanded metal lath is well-known, see for example U.S. Pat. Nos. 1,017,255; 2,167,208; 2,213,603. Such use of perforated elements such as sheets, cellular sections and non-cellular sections also is well-known, see for example U.S. Pat. Nos. 460,850; 2,200,636; 2,357,560. Such use of stud-like elements also is known, see for example U.S. Pat. No. 1,561,518.
The use of field applied stud-like elements and expanded metal lath is a time-consuming and expensive method of promoting mechanical locking of the subsequently applied fireproofing material. The use of perforations to promote mechanical locking cannot be considered inasmuch as the longitudinal cells, to serve as electrical raceways, must be substantially imperforate.
Decking sections having keystone-like ribs and the use of such ribs as attachment sites for hanger devices is known in the art, see for example U.S. Pat. No. 3,812,636. However, keystone-like ribs can only be used as attachment sites for hanger devices, where the keystone-like ribs are provided in non-cellular decking sections.
Many methods of manufacturing expanded metal lath are known in the art. One method of manufacturing expanded steel truss members is disclosed in U.S. Pat. No. 3,034,197.